Herbicidal 3-methyl-5-ureidoisothiazoles



United States Patent 3,454,591 HERBICIDAL B-METHYL-S-UREIDOISOTHIAZOLES Heinz Schulz, Friedrich Arndt, Georg-Alexander Hoyer, and Reinhart Rusch, Berlin, Germany, assignors to Schering A.G., Berlin, Germany No Drawing. Filed Apr. 21, 1966, Ser. No. 550,875 Claims priority, application Germany, May 8, 1965, Sch 37,022 Int. Cl. C07d 91/32 U.S. Cl. 260-306.8 11 Claims ABSTRACT OF THE DISCLOSURE Novel 3 methyl 5 ureidoisothiazoles are provided which may be utilized as selective herbicides.

The invention relates to novel derivatives of urea and thiourea. More particularly, it relates to urea and thiourea derivatives having herbicidal effects, and distinguished by their selectivity as to herbicidal effects.

Heretofore, urea derivatives having herbicidal effects have been known, however, the selectivity of such known agents has not always been satisfactory.

It now has been found that compounds of the formula wherein X is oxygen or sulfur, R is hydrogen or lower alkyl, and R is alkyl or cycloalkyl, are effective herbicides, and are superior to the known urea derivatives in their selectivity.

Compositions containing at least one of these urea compounds have a surprising effect on many kind of weeds when employed in desirably small amounts. Contrary to known urea derivatives, they can be used without detrimental effects on various economically valuable crops which include also important vegetable crops; such as freshly sown onions, freshly sown leeks, and chives. When employed in amounts of 0.5 to 1 kg. of active agent per hectare, the compounds of the invention destroy field weeds such as Chenopodium album, Spergula arvensis, Lamium= amplexicaule, Polygonum convolvolus, Polygonum lapathiolium, Senecio vulgaris, Thlaspi arvense, Urtica urens, Papaver ssp., Galinsoga parviflora, Capsella bursa pastoris, Raphanus raphanistrum, Stellaria media, Matricaria chamomilla, and Sonchus oleraceus. Onions, leeks, and chives sown in the same area, however, are not damaged.

The herbicidal agents of the invention may be applied simultaneously with or after seeding, and it is also possible to treat leafy crops of the afore-mentioned vegetables directly without damaging them.

Many weeds, some of which heretofore could be fought only with difliculty, such as chamomilla, Senecz'o vulgaris, Galinsoga parvz'flora, Sonchus oleraceus, Lamium amplexz'caule, and Chenopodium album, can now be effectively attacked over a wide period of the growing season.

The agents of the invention are therefore also superior to the herbicides employed heretofore in onion fields, such as isopropyl-N-3-chlorophenylcarbarnate which are not adequately effective against such field weeds. Aside from onions, leeks and chives, grain and corn crops can also be treated with great success against weeds without crop damage. It is further possible to destroy weeds in cabbage crops and in sown radishes. Furthermore, one of the compounds namely 3-methyl-5-N-methylureidoisothiazole employed in the herbicidal compositions of the invention is suitable for combating weeds in waste land.

The new active agents of the compositions of the invention are prepared in well known manner, by the reaction of 3-methyl-5-an1inoisothiazole with either (a) the corresponding alkylisocyanates or alkylisothiocyanates in an inert organic solvent, or with (b) carbamoyl or thiocarbamoyl chlorides in the presence of an acid receptor, such as an inorganic or organic base, preferably pyridine.

Preparation of 3-methyl-5-N-methylureidoisothiazole according to method (a) aboveg. (0.88 mole) 3- methyl-S-amino-isothiazole were dissolved in 960 ml, anhydrous tetrahydrofuran, and 59.5 ml. (1.0 mole) methyl isocyanate were added drop by drop. The compound resulting began crystallizing after a few minutes during which the reaction is distinctly exothermic. The reaction mixture was refluxed for three hours to complete the conversion. It was then permitted to cool, filtered with suction and the resultant precipitate was washed with ether, whereupon 210 g. of a product of MP. 217.5 to 219 C. were obtained. An additional 12.5 g. of the product (M.P. 216-218 C.) were obtained upon partial evaporation of the mother liquor. The total yield therefore, was 222.5 g., corresponding to 98.9% of theory.

When recrystallized from acetonitrile or water, a colorless product having a M.P. 222 to 223 C. was obtained which was analyzed as follows:

Calculated: N, 24.54%; S, 24.34%; S, 18.45%.

Suitable solvents that may be used other than tetrahydrofuran include other others as well as aromatic hydrocarbons and ketones, such as acetone, methylethyl ketone, etc.

18.73%. Found: N,

Preparation of 3 methyl 5 N,N-dimethylureidoisothiazole according to method (b) above.11.4 g. (0.1 mole) 3 methyl 5 amino isothiazole were dissolved in 30 ml. pyridine and mixed with 11 g. (0.1 mole) dimethylcarbamoyl chloride. The mixture slowly and spontaneously heated up. When the temperature reached 50 C., the mixture was cooled with ice water, and was left to stand over night, whereupon it was poured on ice. A resultant yellowish brown powder precipitate was filtered off with suction, washed with water, and then dried in a desiccator, 3.5 grams of the product were obtained. The melting point was C., decomposition, after recrystallization from acetonitrile. The structure was made probable by infrared spectrum (intensive carbonyl bands).

3 A few other active agents of the invention prepared according to the methods described above are listed below.

herbicide in onion crops, did not attach the Galinsoga parviflora. Other urea derivatives which have become known as herbicides, and the mixture of 'butinyl-N-3-chlorophenyl-carbamate and N-cyclooctyl-N,N'-dimethyl- Compound: Melting point a urea also d stro d th cr 1 t 3-methyl-5-N-methyl-ureidoisothiazole 222-223 5 6 ye 6 OP P an 3-methyl-5-N-ethyl-ureidoisothiazole 191-193 3-methyl-5-N-propyl-ureidoisothiazole 164-166 Effectiveness 3-methyl-5-N-isopropyl-ureidoisothiazole 199-200 Active agents Onions Gall-mm? 3-methyl-5-N-n-butyl-ureidoisothiazole 138139 3 meth 5 cloh x 10 i-ir1ethyl-5-N-metl1yl-ureidoisoth azole 1O y y e y ure 1 150 1 d-mothyl-S-N,N-dimetliyl-ureidoisothiazole 10 zole 200-201 gfi l-gg-e gy -u reidogothiegole 10 2 -me y- -nu y-urei oiso iazo e 10 0 3 methyl 5 N-methyl-thioureidoisothia- 3-methyl-5-N-eyclohexyl-ureidoisothiazole i0 01e, 209-210 g-mei zgyl-eg-methyl-thiou eidofiethiazole l0 0 -me y-5- -n-propy -urei oiso iazo e- U 3-methyl-5-N-ethyl-thioureidoisothiagole 195-196 3-methy1-5-N-isopropyl-ureidoisothiaz010.. 1o 0 3 methyl 5-N-1sopropyl-thioureidoisothiagggfi ig gp pv wu e om Z016 205 N;-3,4-dieh1o'rb' 5i1ii'y1'-i iIfi-diiiiethyidiiI 0 6 3 methyl 5 N,N-dimethyl-ureidoisothia- N r p y y-N- methylurea 0 0 Z016 175 (decomps) Butinyl-N-B-chlorophenyl-carbamate+N- cyclooctyl-N-,N-dimethylurea 0 0 The active agents of the invention may be employed Isopropyl-N-3chlorophenyl-carbamate 10 10 singly or in mixtures with each other and/or with other Untreated herbicides, such as derivatives of urea, carbamates, ani- 0=T0tally destroyed. 10=Undamaged.

lides, triazines, and/or with other materials, such as fertilizers. The active agents are preferably compounded in EXAMPLE 2 the customary manner for combating weeds, for example, Th 1 b in powders, spreadable compositions, granulates, solue acme agePtS fsted be P were aPPhed y spray tions, emulsions or suspensions, With added liquid and/ mg 6116110? (Smap's and tPmatOeS used as or solid carriers or diluents, and also with wetting agents, test Plants m greenhouse ixpenmifntsi m amounts of 10 adhesion promoters, emulsifiers and/or dispersing agents. gzg i g i 300 ltlters s? f f f' The various con ositions are re ared in the usual f 6 69 e agens aCC r ing 0 e inmanner, for example, by grinding; oi mixing, as is cus- Venuon evldem from the resultstomary in crop protecting materials, liquid or solid inert carriers or diluents, and surfactants being added as need- Active agents sinapis Tomatoes ed. Suitable solid carriers in the resultantly used compo- 3m th 15 Nm th 1 w 1 0 sitions include lime, kaolin, chalk, talcum, natural or j g g j g ggg ggiggg gggg 0 8 synthetic silica, attaclay, and other types of clay. Liquid i age}-glgI -n gufy -uguggo thla ole. 3 8

carriers or diluents are less suitable because the very lirri- 1$, g j jfi igi iiitfli ggffi 3 1 1 ited solubility of many active agents of the invention in gezl yl-gg-methyl-thiou eiglofiethiz zole- 8 3 organic solvents. Applicable surfactants include salts of 53g, g i jgg gg i,gfi, fg,,fgfg $55,; 0 1

lignosulfonic acid, polyethoxylated amines and alcohols, g e g i-gg-e: y -th iu e do so thia gle.... 2 5

esters of alkylaryl polyglycol ethers, salts of alkylated 0 1 benzenesulfonic acids, and sulfonated acid amides and eated 10 10 salts- 0=Totally destroyed. 10=Uiidamaged.

The following examples further illustrate the invention.

EXAMPLE 1 EXAMPLE 3 One kilogram per hectare of each active agent listed Sown onions (strain yellow Zittsuer), sown leeks of in the table was suspended in 800 liters water per hectare strain Elefant, and chives were treated in an open field and applied by spraying to young plants of onions and prior to germination with 3-methyl-S-N-methyl-ureidoiso- Galinsoga parviflora after germination. It was found that 5 thiazole and isopropyl-N-3-chlorophenyl-carbamate, for the agents of the invention did not damage the onion comparison, at the rates indicated below. The herbicidal ero whereas the destro ed the Galinso a arvi ora a ent of the invention had a substantiall better weed- P Y g P Y weeds. By way of comparison, the isopropyl-N-3-chlorokilling effect in an amount which was one-sixth of the phenyl-carbamate, which is commonly employed as a amount of the compared material.

Amount of active agent, Stellaria La nium Urtica Galinsoga Active agents kg ./ha. Onions Leeks Chives media ampleztcaule arms parvijlora 3-methyl-5-N-inethyl-ureidoisotliiozole 0. 5 910 9-10 10 0 x o o Isopropyl-N-S-chlorophenyl-carbamate 3 9-10 9-10 10 0 xxx 0 xxx Untreated xxx xxx xxx x Evaluation scale for crop plants: 0=Totally destroyed. 10=Undamaged. Evaluation scale for weed: 0=Free of weed. x=Weed present. xxx=Weed dominating.

Amount of Polygonum C'apsela active agent, Se'neciovallapathi- Polygonum Sonchus Chenopodium Raphanus bursa Sperqula Active agents kg./ha. garis folia'mc onvolvulas oleraceus album raphanistrum pastarz's arvensis 3-methy1-5N-methy1- ureidorisothioz0le 0. 5 0 0 0 0 0 0 0 0 Isogropyl-N-lic lorophenylcarbamate 3 x 0 0 0 0 0 0 0 Untreated l xxx x x x x x 1U= Untlamaged.

xxx=Weed dominating.

5 EXAMPLE 4 Onions, corn and weeds were treated in an open field compatibility with the various types of cabbage while having good herbicidal effects against weeds.

before and after germination with 3-methyl-5-N-methyl- 3 1119 Y ureidolsothiazole and with two urea derivatives WhlCh are 5 1 1 mm U d is t t a known herbicides at a rate of 1 kg. active agent suspended mo 8 n N m in 800 liters water per hectare. The compound of the in- 8 10 Kohlrabi (Brassica oleracea var. ventlon showed excellent effects agamst weeds and good gongwzodex L) M 10 selective compatibility With sown onions and corn. This 10 35 3252 13 9 6 10 selective com atibilit was not observed with the kn Brussels 89555513515555;52555555 I I P Y own gemmifera (DC) Thellurea derrvatives. Cauliflower (Brassica oleracea var.

botrytis L.) 10 10 Green cabbage (Brassica oleracea var.

acephala f. crispa (DC 10 10 1 Red cabbage (Brassica oleracea var.

capitata f. rubra L.) 8. 6 Polygonum convolvulus 1. 5 10 Chenopodium album 1. 7 10 Spergula arvensis 1. 0 10 0=Totally destroyed. 10=Undamaged.

Lamium Chenopod ampleri- Senecio Thluspi Urtica Papaver Galinsoga Active agents Corn Omons iumalbum cattle vulguris arvense urens esp. parviflom 3-methyl-5-N-methylureidoisothiozole:

10 10 0 0 0 0 0 0 0 (b) 10 10 0 0 0 0 0 0 0 N-3,4-dichlorophenyl-N-methoxy-N- methyl-urea:

a) 10 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 N-4-chloro-phenyl-N-methyl-urea:

(b) 7 0 0 0 0 0 0 0 0 Untreated .IIII 1o 10 10 "10 "i6" i6 10 "i6 "i6 (a) =Beiore germination. (b) =After germination. 0=Totally destroyed. 10= Undamaged.

EXAMPLE 5 EXAMPLE 7 I Grain in the two-leaf or dicotyledenous stage and a Weeds in open Waste land were treated with S-methylstand of numerous :weeds in the twoto six-leaf stage or paired-leaf stage were treated in a greenhouse with aqueous suspensions containing 3-methyl-5-N-methylureidoisothiazole and the known herbicide N-methyl-N-4- chlorophenyl-urea respectively. The evaluation figures in the following table relate to the eflects fourteen days after spraying. While the compound of the invention did not damage the grain and completely destroyed the broadleafed weeds, the grain was somewhat damaged and its growth was strongly aifected by the known urea derivative, and only Galinsoga parviflora, among the weeds tested here, was completely destroyed.

Active agents EMMPLE 6 Various types of cabbage were planted in sandy soil in fields and radishes were sown, and were treated 2% weeks later with 3-methyl-5-N-methylureidoisothiazole at a rate of 2 kg. suspended in 1000 liters water per hectare. At the time of spraying, the cabbage was in the four to six leaf stage. The radishes were in the germination to two leaf stage. The weeds present were Chenopolium album with four to six leaves, Spergula arvensis with one to four leaf whorls, and partly older bunches, and Polygonum convolvulus with one to two leaves. The following table shows the results of evaluation four weeks after the treatment. It was found that the 3-methyl5-N-methylureidoisothiazole of the invention has relatively good selective 5-N methylureidoisothiazole at a rate of 5 kg. active agent suspended in 800 liters water per hectare. The treatment was successful in almost completely eliminating the weeds present.

3-methyl-5- N -methylureidoisothiazole Untreated Achillea millefolium 1 10 Tan acetum vulgare 2 10 0=Tota11y destroyed. 10= Undamaged EXAMPLE 8 Preparation of a Wettable powder The following ingredients were mixed in an air jet mill:

Percent by weight One of the new active agents of the invention 50 Calcium lignosulfonate l5 Al-kylarylpolyglycol ether sulfate 2 Attaclay 33 The herbicidal composition prepared according to Example 8 can be mixed with water to form an aqueous 11. A compound of the formula H3CC CH X R I NH N 7 8 wherein X is oxygen or sulfur, R is hydrogen or lower 2,639,285 5/1953 Sondern et a1 260-306.8 alkyl, and R is lower alkyl or cyclohexyl.

NICHOLAS S. RIZZO, Primary Examiner. References Cited R. I. GALLAGHER, Assistant Examiner.

5 UNITED STATES PATENTS Us. CL XR.

2,470,585 5/1949 Sperry 260--306.8 71-90 

